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Federal lawsuit filed over castings of dinosaur bones Read more: Federal lawsuit filed over castings of dinosaur bones

Bones from two dinosaur specimens have prompted a federal lawsuit in a dispute between two organizations that preserve fossils.

A South Dakota research company is suing a Montana nonprofit dedicated to the study of fossils over castings of bones from two tyrannosaurus-rex specimens discovered in South Dakota.

The Black Hills Institute of Geological Research in Hill City, S.D., argues that it lent two castings to Fort Peck Paleontology in Montana several years ago.

In the lawsuit filed Tuesday in U.S. District Court in Great Falls, Mont., the institute claims Fort Peck Paleontology failed to return the castings and is using them to sell unauthorized copies of the bones.

Read more: Federal lawsuit filed over castings of dinosaur bones - The Denver Post http://www.denverpost.com/headlines/ci_16713098#ixzz19f9X8JuT
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Source from :http://www.denverpost.com



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Doubt cast over dinosaur stampede theory

Scientists are now trying to determine what type of dinosaur left footprints at Lark Quarry about 95 million years ago.

For 30 years, scientists have believed the footprints at Lark Quarry were made by a large carnivorous dinosaur chasing down smaller reptiles.

However, University of Queensland researchers Anthony Romilio and Steve Salisbury have released a scientific paper and Dr Salisbury says it is an exciting finding.

"With the realisation that this is probably a big plant eater, we now really have to question the whole stampede scenario," he said.

"Would a big, plodding plant eater like muttaburrasaurus cause a herd of small dinosaurs into a stampede - it is exciting stuff."

He says the research has been peer-reviewed before being published.

"Just looking at the big tracks and the amount of comparison that we've done ... I think we're fairly confident that we've come up with a fairly reasonable hypothesis for what occurred there," he said.

"It looks like it was a big plant eater and so that kind of changes things a little bit in terms of what is happening out at Winton with regard to the dinosaur story."

'Grey area'

But Winton dinosaur expert David Elliott, from the Australian Age of Dinosaurs Museum, has been involved in a project at Lark Quarry with the Queensland Museum and he believes the carnivorous dinosaur theory holds.

"Our research is drawing a vastly different conclusion to that reached by Mr Romilio and Dr Salisbury," he said.

Mr Elliott says their results are due out shortly.

"The Lark quarry 'trackways' is always going to be controversial because it is one of those grey areas of science," he said.

"We are looking on relevant new discoveries among well documented scientific data," he said.

"We definitely do believe that that is the case [that it is a meat eater] and the evidence that has always historically pointed to that has been gathered and studied by some very, very capable palaeontologists over the past 35 years.

"We can't and we shouldn't just simply discard their work on the strength of the opinion of the first work to the contrary."

Source from :http://www.abc.net.au



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Raptor-like dinosaur discovered in eastern Utah

A small, feathered raptor-like dinosaur thought to be 125 million years old has been discovered in eastern Utah, scientists announced Thursday.

The Geminiraptor suarezarum was bipedal and, like other raptors, had a large head. Most of the known raptors discovered in North America date to between 72 million and 75 million years ago, which makes the discovery the oldest reported specimen of its kind.

"They were fast, they were smart, they had big eyes and very dexterous hands," said James Kirkland, a paleontologist with the Utah Geological Survey.

It was the eighth new species of dinosaurs discovered in Utah this year. Seven of those were found on federal land.

The G. suarezarum was discovered on federal land near Green River, an area about 180 miles southeast of Salt Lake City that has become notable for the number of new species discovered there. The College of Eastern Utah's Prehistoric Museum in Price is curating the bones and overseeing the excavation of the quarry where the bones were found.

The quarry was found seven years ago by identical twins Celina and Marina Suarez of San Antonio, Texas, for whom the new species was named. The 29-year-old paleontologists were helping Kirkland excavate a different quarry just over a mile away.

The quarry, now called "Suarez Sister's Quarry," has since yielded two dinosaur discoveries. Kirkland said that they are also studying bones that may prove to be a third new dinosaur.

"We both knew it would be significant," Celina Suarez said. "But we never thought it would have this much."

Having a dinosaur named after them is unbelievable, she said.

"As kids, we always kind of thought we might dig up a dinosaur in our backyard," she said. "We didn't know we would have to drive to Utah to do it."

Kirkland said that honoring the sisters reflected not only their discovery of the quarry, but also their passion for paleontology.

Source from :http://news.yahoo.com



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Carcharodontosaurids

The carcharodontosaurids were a group of giant carnivorous dinosaurs that rivalled and even exceeded Tyrannosaurus in size. Scientists have calculated that one of them, Giganotosaurus, could run at 50 km/h, which is just slower than an ostrich, but 13 km/h faster than a gold medal-winning Olympic sprinter. Carcharodontosaurids were top predators in the ancient continent of Gondwanaland: the area of the world that's now the southern hemisphere continents - South America, Africa, Antarctica, Australia - and India. They evolved from an Allosaurus-like ancestor and became extinct about 89 million years ago.

Scientific name: Carcharodontosauridae
Rank: Family
Common names: Shark-toothed lizards


Source from :http://www.bbc.co.uk



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Dromaeosaurs Dinosaurs

Dromaeosaurs - also called raptors - were carnivorous dinosaurs closely related to birds. Several dinosaurs fossils have been found with evidence of feathers, and many scientists believe that the whole group had an insulating covering of feathers. All dromaeosaurs have a large, sickle-shaped claw on each hind foot, which helped them climb. Small species probably climbed trees, but there is speculation that larger ones used their claws to cling on to prey and as weapons. Dromaeosaur species ranged from about 1.5 to 9 metres long.

Scientific name: Dromaeosauridae

Rank: Family
Common names:

* Raptors,
* running lizard

Source from :http://www.bbc.co.uk



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Coelophysis Dinosaurs

Coelophysis were one of the earliest of the meat-eating dinosaurs from the late Triassic period. Analysis of the numerous well-preserved skeletons found in a quarry in New Mexico has suggested that Coelophysis were small, yet fast and agile predators, powered by strong hind limbs and aided by a long, slender tail. The long jaw was filled with typical meat-eater's teeth: sharp, serrated and blade-like. Small animals would have been hunted by sight as Coelophysis had relatively large eyes. So many skeletons all found together suggests they may have lived or hunted in packs.

Scientific name: Coelophysis

Rank: Genus
Common names: hollow form


Source from :http://www.bbc.co.uk



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Dinosaurs' dominance 'helped by mass volcanism'

Dinosaurs were the dominant vertebrates on land for some 135 million years.

While it is widely accepted that an asteroid or comet wiped them out, there has been less agreement on the factors which led to their ascendancy.

Research in PNAS journal suggests volcanic eruptions changed the climate, causing a mass extinction that wiped out the dinosaurs' main competitors.

The scientific paper, by researchers from the US and Taiwan, looked at several lines of evidence such as the remains of plant wax and wood from sedimentary rocks interbedded with lava flows. From these, they were able to extract vital data about the climate at this time.

The lava flows are dated to the end-Triassic extinction, 201.4 million years ago, which wiped out 50% of tetrapods (four-limbed animals) on land, 50% of terrestrial plants and 20% of marine families.

The scientists examined how two different isotopes (or forms) of carbon fluctuated during these volcanic eruptions. They found that the "heavy" form of carbon was depleted relative to the "light" form.

Super greenhouse

They say this reflects disturbances in the carbon cycle at this time, including a spike in atmospheric carbon dioxide (CO2) and aerosols (fine solid particles).

This would have resulted in "super" greenhouse warming, according to lead author Jessica Whiteside, a geologist at Brown University in Providence, Rhode Island.

"We are showing that these events are synchronous with the extinction and that the events all occur within a few tens of thousands of years of the eruption of these huge lava flows," Dr Whiteside told BBC News.

The scientists have not yet determined the killing mechanism behind the mass extinction.

Neither can they say for sure why the dinosaurs survived it, although Dr Whiteside suggests it could have been "blind luck".

Nevertheless, they propose that the climatic catastrophe caused by the mass eruptions led to the extinction of the dinosaurs' main competitors, the crurotarsans.

These ancient crocodile-like creatures had competed vigorously with early dinosaurs during the Triassic Period.

The study is not the first to posit a link between volcanic activity and the end-Triassic mass extinction.

But the relationship between volcanism, carbon isotope anomalies and extinctions had never been tested in rocks preserving records of all three phenomena. The scientists say this is the first study to do so.

Big break-up

The so-called volcanic "flood basalts" form a giant geological entity known as the Central Atlantic Magmatic Province (Camp).

This was formed during the break up of the "supercontinent" known as Pangaea, causing lava to pour out on to the Earth's surface for some 700,000 years.

"This is actually the largest flood basalt province known in the Solar System. It covers something like 9-11 million sq kilometres. To give you an indication of how large that is, it's about one-third the size of the Moon," said Dr Whiteside.

"We're talking about a serious amount of the Earth being covered in lava."

It dwarfs the Deccan traps, a large igneous province in west-central India. The volcanism which created the traps had been implicated by some in the extinction of the dinosaurs 65 million years ago.

Earlier this month, a panel of experts strongly endorsed evidence that a space impact was instead responsible for this extinction.

Writing in Science journal, they ascribed the cause to a 10-15km space rock striking the Yucatan Peninsula. This caused a global winter that played havoc with marine and land ecosystems.

Source from :http://www.bbc.co.uk



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Dinosaur's oldest relative found

Asilisaurus kongwe is a newly discovered herbivore that lived during the middle Triassic period - about 245 million years ago.

The scientists say that its age suggests that dinosaurs were also on the Earth earlier than previously thought.

They described their findings in the journal Nature.

The study was led by Dr Sterling Nesbitt from the University of Texas at Austin in the US.

He said: "This new evidence suggests that [dinosaurs] were really only one of several large and distinct groups of animals that exploded in diversity in the Triassic period, including silesaurs [like this one], pterosaurs, and several groups of crocodilian relatives."

Dr Randall Irmis from the Utah Museum of Natural History in the US was also involved in the study. He said that this group of creatures - the silesaurs - were the "closest relative of the dinosaurs".

"It was to dinosaurs much like chimps are to humans - kind of cousins," he told BBC News.

"Since we have one line of the family tree, the other branch must have existed at the same time. So this suggests there are other very early dinosaurs that we haven't found yet."

He also said that the creature was not what the researchers expected an early dinosaur cousin to look like.

"It was a weird little creature," he said. "We always thought the earliest relatives were small, bipedal, carnivorous animals.

"These walked on four legs and had beaks and herbivore-like teeth."

'Failed experiment'

Dr Paul Barrett, a palaeontologist from the Natural History Museum in London said that the finding provided scientists with important information about how dinosaurs evolved.

"The creatures share a lot of features with dinosaurs," he said. "They show us an intermediate step between more primitive reptiles and the more specialised dinosaurs."

The fossil record indicates that this group of primitive creatures went extinct approximately 45 million years after they emerged.

The dinosaurs, on the other hand, were far more successful and walked the Earth for about 165 million years.

Source from :http://www.bbc.co.uk



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Missing link dinosaur discovered

This could help to bridge an evolutionary gap between the two-legged common ancestors of dinosaurs and the four-legged giants, such as diplodocus.

The remarkably complete skeleton shows that the creature was bipedal but occasionally walked on all four legs.

The team reports its discovery in the Royal Society journal Proceedings B.

"What we have is a big, short-footed, barrel-chested, long-necked, small-headed dinosaur," explained Adam Yates, the scientist from the University of Witwatersrand in Johannesburg who led the research.

"The earliest ancestral dinosaur - the great grand-daddy of all dinosaurs - walked on two legs. This [one] is intermediate between those bipedal forms and the true gigantic sauropods."

The skeleton was discovered at a site in the Senekal district of South Africa.

Dr Yates explained that features of its feet and jaw, as well as its size, gave away its significance.

The dinosaur, Aardonyx celestae was a heavy, slow-moving animal.

"It had a lot of features we see on sauropods," explained Dr Yates. "Short, broad feet and a big, broad gut, so it was clearly a plant-eater that was bulk-feeding.

"And the anatomy of the jaw shows it had a wide gape - to stuff more food in."

It also had, he said, "sauropod-like front feet".

"Its toe bones were very robust and solid, so its weight was being born on the inside of the foot. It was still bipedal, but it may have been going down on to all fours to browse."

'Living fossil'

The dinosaur dates from the early Jurassic period - about 200 million years ago.

"Although structurally it's intermediate, it lived too late to be an actual ancestor, because true sauropods already existed [then].

"So, at the time, it was a living fossil - the transition must have happened much earlier."

Dr Yates stressed that the site where the fossil was discovered provided an abundance of valuable knowledge about dinosaur evolution.

"If you want to study how the dinosaurs became giants," he said. "You have to come to South Africa."

Dr Paul Barrett - a palaeontologist from the Natural History Museum in London said that the discovery of Aardonyx helped "fill a marked gap in our knowledge of sauropod evolution".

"[It shows] how a primarily two-legged animal could start to acquire the specific features necessary for a life spent on all fours.

"Evolution of this quadrapedal gait was key in allowing the late sauropods to adopt their enormous body sizes."

Source from :http://www.bbc.co.uk



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Ceropod dinosaurs

Ceropod dinosaurs were all plant-eaters and include the horned and duck-billed dinosaurs. The secret of their success was in their teeth. These were much more efficient at grinding up plant food than your typical dinosaur's dentition, so cerapods were able to extract more nutritional value from their food and tackle plants that others found too tough to digest. It wasn't until big herbivorous mammals evolved that such efficient chewing teeth were seen again on Earth.

Source from :http://www.bbc.co.uk



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Triceratops Dinosaurs

Together with the bony frill behind its extraordinarily large head, the three distinctive horns of the Triceratops were traditionally viewed as defensive weapons for this mighty herbivore.

However, it is likely that they were used in courtship and dominance displays, much as modern deer use their antlers. One of the last groups of dinosaur to evolve, Triceratops would have shared the landscape with, and been preyed upon by, the awesome Tyrannosaurus.

There is little evidence that they ever had the spectacular battles so often depicted, however. No complete Triceratops skeleton has yet been found and what was thought to be another horned dinosaur, Torosaurus, has recently been identified as the fully mature form of Triceratops.

Source from :http://www.bbc.co.uk



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Ornithopod dinosaurs

With some of the most advanced chewing apparatus ever developed by a reptile, ornithopod dinosaurs became a most successful group of herbivorous dinosaurs. They rapidly became a prominent feature on North America's Cretaceous landscape, until they were wiped out by the famous Cretaceous-Tertiary, or K-T, extinction event. Early ornithopods were only about a metre long and could probably run very fast on their hind legs. They evolved to become as large as some of the mighty sauropods, walking and grazing on all four legs, but still using the hind legs for running and reaching up into trees. Notable ornithopods include the duck-billed hadrosaurs and, of course, iguanodon.

Source from :http://www.bbc.co.uk



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Lizard-hipped dinosaurs

The earliest known dinosaurs, lizard-hipped dinosaurs first appeared in the mid Triassic. As well as these first dinosaurs, the order includes all the carnivorous dinosaurs and one group of herbivores - the sauropods and their close relatives. The name 'lizard-hipped' comes from the shape of their pelvis, in which the pubis points towards the front of the animal. Birds are descended from this group of dinosaurs.


Source from :http://www.bbc.co.uk

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Bird-hipped dinosaurs

Bird-hipped dinosaurs derive their name from the shape of their pelvis, which resembles that of modern birds, whose pubis points to the rear of the animal. Unexpectedly, birds did not evolve from these dinosaurs, but from the lizard-hipped dinosaurs, since this shape of pelvis has evolved more than once. Another distinguishing characteristic of the bird-hipped dinosaurs was a horny beak, which they used to crop plants, much like a horse or deer uses its front teeth today. Duck-billed dinosaurs, horned dinosaurs and armoured dinosaurs were all of the bird-hipped variety.

Source from :http://www.bbc.co.uk

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Dinosaur Timeline

Introduction

The history of the planet Earth is divided into a bunch of time chunks so whether you’re looking at a time which existed 100 years ago or even as far back as 1000 million years ago you’ll need to learn the lingo used to classify each of these sizable time periods. The most important of these are aeons, eras and periods.

The rest of this article will go onto explain the timeline that the dinosaurs existed in so if you’re not familiar with the terms aeon, era and period we recommend you take a look at our timeline defintions page here, otherwise read on to learn more about the age of the dinosaurs.

The Age Of The Dinosaurs

The Dinosaurs and many of the other large prehistoric reptiles existed in the Mesozoic era of the Phanerozoic aeon. The Mesozoic era ran from about 250 million years ago to 65 million years ago. Thats 185 million years of Dinosaur domination, no wonder the Mesozoic era was commonly referred to as the age of the Dinosaurs.

The Mesozoic era contained three periods known as the Triassic, Jurassic and Cretaceous periods. Over the next few sections we will try to cover the key charcterstics of each period to give you an overall understanding of when and where certain dinosaurs existed as well as smashing some of the common myths and misconceptions surrounding that time period.

The Triassic Period

The Triassic Period is the first phase of the Mesozoic era and spanned for an interval of 35 million years from 250-205 million years ago. Planet Earth was a very different place back then with the most common difference being that all the continents were united to form one huge c shaped land mass or super continent known as Pangaea meaning “all lands”.

More about the Triassic Period.
The Jurassic Period

The Jurassic Period was the second phase of the Mesozoic Era. The time scale for this famous period is from 205 to 138 MYA (million years ago). This period was named after the Jura Mountains because of the exposure and discovery of the marine lime stones.

More about the Jurassic Period.
The Cretaceous Period

The Cretaceous Period was the last period of the Mesozoic era and marked the end of the dinosaurs. It spanned a time from 138 million to about 65 MYA (million years ago). In this period the continents fully separated. However, Australia and Antarctica were still united.

There were important things that happened in this period such as the development of flowering plants like the magnolias and water lilies and the increase in the number of different kinds of insects. This was the beginning of the modern insects such as the ants, butterflies, grasshoppers, termites and aphids.

Source from :http://www.dinosaur-facts.com

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Getting Started With Dinosaur Learning

Introduction

Lets face it if you’re knowledge about dinosaurs is what you’ve learnt from the movie Jurassic Park then you’re missing a massive junk of interesting facts and details regarding a very important and interesting period of our planets history.

Before we started this site we realised that for many people their familiarity with prehistoric reptiles extended as far as a handful of dinosaur names such as the Tyrannosaurus Rex, Brachiosaurus, Stegosaurus and maybe a few others. That level of knowledge is fine for some, but there were others who wanted to dig deeper into this subject but were unable to, due to it’s overall size and complexity.

We acknowledged this problem and came up with our learning center which aims to offer an easy introduction and explanation into the core subjects surrounding the study of dinosaurs. Our hope is that the learning center will uncover the basic fundamentals allowing normal people to ease into the more detailed and often more exciting aspects of the dinosaur world.
Where To Start

The subjects we think you need to cover and understand before you dig deeper into your dinosaur studies are listed below. Simply work your way through each topic making sure you understand them well enough to be able to teach others.

If you can do that then you’re more than qualified to start on the more detailed subject areas and really advance your learning.
Core Subjects

* The Dinosaur Timeline
This section will introduce you to when, where and how long ago the Dinosaurs existed. Some basic references to different types of dinosaurs as well as the condition of the planet during the three dinosaur periods is covered.
* The Dinosaur Groups
This section gets a little technical but its also an eye opener into the various types of reptiles that existed at the time of the dinosaurs. So many reptiles that weren’t actually dinosaurs get called dinosaurs, its a massive misconception and the movies dont make things any better. You will learn not only about dinosaurs but pterosaurs, plesiosaurs and afew other non dinosaur groups. You’ll feel pretty clever after you finish this section.
* Dinosaur Extinction
This section builds on the timeline and again clarifies some of the theories and events that possibly happened and lead to the extinction of the dinosaurs. Remember the dinosaurs didn’t all become extinct at the same time, there were many extinctions happening throughout the Mezosoic era which meant that many of the dinosaurs we commonly know of didnt even exist at the same time.
* Dinosaur Fossils
This section covers the modern aspects of dinosaur study, palaeontology and how we learn and uncover the secrets behind this now extinct world. Its not necessarily the coolest section but don’t skip it as it does tie up many of the other sections and of course help you appreciate and understand the rest of the articles on the site.


Source from :http://www.dinosaur-facts.com

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Stegosaurus dinosaurs

Stegosaurus Basics

The Stegosaurus was considered to be the largest of the stegasaurid family and existed throughout the late Jurassic period. It’s name is derived from the Greek word ‘stegos’ meaning roof and ‘saurus’ meaning lizard, making it the ‘Roof Lizard’.

Stegosaurus Fossils & Origins

The very first fossils and relics of the stegosaurus were excavated in the western parts of North America in the year 1877 by Othniel Charles Marsh. In fact it wasn’t until 2006 that more fossils were uncovered outside of North America blowing away the theory that they were exclusive to North America. The 2006 discovery in Portugal was the first of it’s kind in Europe, indicating that the dinosaur existed much further adrift than had once been thought.

Taxonomy & Variations

Despite there being various classifications for the different stegosaurus dinosaurs most of these were based on only a few minor differences in appearance. The foremost among them include the long spined roof lizard or the Stegosaurus Longispinus which measured about 20 ft long and owes its name to its four extraordinarily long tail spines.

The armored roof lizard or stegosaurus armatus was not only one of the first stegosaurus remains to be found but measured about 30 ft in length and possessed much smaller plates compared to the rest of its family. The most popular variant of the stegosaurus was the stegosaurus stenops or the narrow faced roof lizard which was usually shorter than the stegosaurus armatus but had a unique skeletal structure and several huge and expansive body plates.

There are also several other variant species of the stegosaurus which have been discovered from time to time although most of these are still under observation and research, hence not much information is available on them. Some of these include the Stegosaurus Seeleyanus, Stegosaurus Sulcatus, Stegosaurus Affinis and the Stegosaurus Ungulatus.

Physical Features

The stegosaurus was a large bodied dinosaur with a heavy arching back and a tail that was extremely tough and always held high in an upward position. (that’s correct unlike the cartoons, it didn’t drag along the floor).

The stegosaurus measured around 30 ft in length, it had padded hoofs with the forelimbs having five toes and the hind limbs having just three. The overall structure and body shape indicated that the stegosaurus wasn’t a fast moving dinosaur and was most likely a slow wanderer.

The head of the stegosaurus was quite small and insignificant compared to the enormous size of its body. The positioning of the head as is evident from the fossilized remains of the skull also prove that they were herbivores consuming simple vegetation that grew on the forest floor.

Like all herbivores the stegosaurus possessed an extremely efficient dental arrangement which aided in the chewing and grinding of its food. This meant the bone structure of the skull and the jaws accommodated the stegosaurus with cheeks to store food whilst chewing and a set of small triangular, flat teeth which aided in grinding plant matter.

It’s Brain

A very interesting fact that has been noted by scientists is that despite their magnanimous body size, their brains were extremely small. Whilst their body weight stood close to 5 tonnes, its brain weighed a puny 80 grams.

Another interesting theory about the Stegosaurus brain is the concept of a ‘second brain’. Many scientists have said the huge passage near the hip region could easily have housed something like a brain. This theory has been much popularized by scientists who acknowledge that the second brain was essential in organizing and controlling the various functions on the back part of the body.

Plates And Tail Spikes

The most important corporeal feature of the Stegosaurus has to be its plates and the tail spikes which make it stand out among the various dinosaur species. There has been a lot of research regarding the function of these plates and tail spikes and a common consensus has been reached regarding the fact that these spikes and plates were usually used by the stegosaurus for defense purposes.

The stegosaurus comprised of 17 dermal plates shaped like kites having four sides and it should be noted that these were not generated from the bones but rather protruded from the external surface of the skin. These plates are believed to have belonged to a kind of osteoderms which refer to a kind of bony scales on the body and similar bone structures can be observed in most lizards and crocodiles of today. While these plates have been usually considered as being used for defense purposes against marauders who attacked these herbivores, it can be also be noted that they were not enough to guard the stegosaurus completely as the sides remained exposed to attack. However, the plates also have other functions like it helps to regulate body temperature of the stegosaurus though this fact is also debatable.

The stegosaurus possessed about four tail spikes in addition to the 17 dermal plates and these tail spikes were also referred to as thagomizers. The use of the tail spikes have been highly debated from time to time. While a set of evidences do prove that these spikes were indeed used for defense and as a means for protection, it has also been noted that many of the body plates overlapped the vertebrae of the tail thus greatly constraining its movement.


Source from :http://www.dinosaur-facts.com

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Allosaurus Dinosaurs

Allosaurus Origins

The Allosaurus a member of the Allosaurid family was first discovered during the closing years of the 19th century by Othniel Charles Marsh in 1877. It existed in the late Jurassic period about 150 million years ago and almost all of it’s fossils have been in the Morrison Formation in the North America, as well as in Portugal and Tanzania. The name Allosaurus means “different lizard” and is derived from the Greek root word “allos” meaning “different”.

Taxonomy

Like most dinosaurs the Allosaurus is believed to have had many variations of it’s kind. Scientists have thus far classified about seven dominant kinds of which some of the prominent types include Allosaurus Fragilis, Allosaurus Atrox, Allosaurus Maximus, Allosaurus Amplexus.
Physical Features

In terms of physical structure, the allosaurus like most theropods was of a high stature. It’s believed to have grown to about 30ft tall, and being almost 40ft in length. Like the T-rex the most striking feature had to be the size of it’s skull which was enormous compared to the size of it’s much shorter neck. Again like the Tyrannosaurus the Allosaurus possessed a huge tail (acted as a counter balance) and tiny forelimbs consisting of three fingers. It’s estimated weight was around 2.3 metric tons.

Skull & Teeth

The skull of the Allosaurus was estimated to be around 33 inches in length giving it a decent sized jaw size. Each premaxilla (the bones forming the tip of the snout) held five teeth and each maxilla (the bones in the upper jaw) and dentary (the bones of the lower jaw) had around 14 to 17 teeth giving the Allosaurus plenty of teeth for the size of it’s skull.

The teeth became shorter, narrower and more curved as you went towards the back of the skull and were probably constantly replaced during it’s lifetime. It’s no wonder that teeth comprised a significant proportion of the excavated remains of any Allosaurus.

Some other interesting features about the Allosaurus include the presence of 2 horns which sat above and in front of the eyes and the fact that it had some of the best developed sinuses and smelling abilities of the theropods.

Behavioral Patterns & Hunting

Scientists have been united in the fact that the Allosaurus was a voracious predator and one of the most feared marauders amongst the dinosaurs. Their preferred victims were herbivorous (plant eating) dinosaurs like the Sauropods, Ornithopods and the Stegosaurids.

Out of the above, it’s thought that the Sauropods were probably their most favoured food item, due to the extensive presence of Sauropod remains on the teeth of Allosaurus fossils. In the case of Sauropods studies have shown that the Allosaurus probably tore the flesh off from living Sauropods deferring the kill of its prey for some time.

In terms of hunting behaviour it’s believed that the Allosaurus usually hunted in groups and their huge tail was also a vital component in aiding the trapping of other dinosaur variants as prey. This hunting in groups is attributed as a unique feature in the Allosaurus as it has been observed that most vertebrates do not usually hunt in groups.

This carnivorous dinosaur was also extremely protective about its young, often hunting and gathering food for them till they were fully grown and capable of looking after themselves.

Anti Social

The Allosaurus, like most Theropods were not very social and are believed to have been exceptionally reserved. This meant that even interactions with other dinosaurs of their own kind were met with distaste. Some scientists believe that the Allosaurus often wounded members of it’s own clan if any miscommunication or misunderstanding happened. The results of these interactions could often be fatal.

Several scientists believe that the Allosaurus may even have scavenged off the remains of other dead or immobilized Allosaurus dinosaurs.

Allosaurus Young

One of the key differences between the adult and child Allosaur was the huge difference in hind limb length. The hind limbs of a child allosaurus were often considerably longer than the adults which allowed them to move swiftly and catch much smaller and faster types of prey. This would suggest that as the Allosaurus matured it would start hunting larger and stronger prey as it would be incapable of capturing the faster dinosaurs that it might have hunted when younger.

Source from :http://www.dinosaur-facts.com

For more information related to dinosaurs, visit rareresource.com.

Triassic Period

Introduction :

The Triassic Period is the first phase of the Mesozoic era and spanned for an interval of 35 million years from 250-205 million years ago. Planet Earth was a very different place back then with the most common difference being that all the continents were united to form one huge c shaped land mass or super continent known as Pangaea meaning “all lands”.

Two Extinctions & The Dinosaurs :

This was an interesting time period because on the one hand a single continent allowed for the free movement of animal species from one region to another, hence diversification and change was common but on the other hand it was also the time of the largest mass extinction ever to occur on the planet Earth.

This mass extinction also known as the “Great Dying” accounted for the loss of over 95% of the then existing marine life as well as 70% of the terrestrial life. This wasn’t the extinction of a single species or a group of species but everything from plants, animals, insects, fishes and pretty much most living things were totally wiped out. Some say that up to 99% of the living species of the world were gone in the blink of a prehistoric second.

Note that dinosaurs didn’t actually exist this early in the Triassic so this particular extinction is not to be confused with the second extinction which also occurred in the Triassic but towards its end. As far as dinosaur existance is concerned it was after the first mass extinction that both mammals and dinosaurs came into being but we’ll talk about that later.

The direct cause of the first extinction also known as the Permio-Triassic Extinction has baffled scientists for years and although there is very little evidence to pin point exactly how things ended there are a couple of theories which range from massive volcanic eruptions, to a large asteroid hitting the planet, or even a simple rise in temperatures due to the formation of the super continent. Any one of these events could have totally destroyed the Earths ability to support plant and animal life but we can never be sure.

Triassic Plant Life :

The general weather and climate throughout the Triassic was very warm and arid. This was due to the lack of oceanic exposure and meant that the central region was primarily desert so plant life really only survived in the northen and southern hemispheres.

No flowering plants existed at this time so most plant life looked pretty boring as a mix of browns and greens. In general the plant life of the Triassic consisted of cycads, lycophytes (mosses), Glossopterids (seed ferns), Ginkoes as well as other seed plants like conifers.

Triassic Animal Life :

Coming into the Triassic the animal life consisted of species that had either survived the Permian-Triassic extinction or had newly appeared after the extinction. This factor alone made it a very interesting time period with many new appearances.

Insects and many other invertibrate species were extremely common and dominant in the Permian period, however only a few of these made it into the Triassic. In fact the Permian contained some of the largest insects ever recorded, sadly most of these did not survive into the Triassic and instead and new form of modern insect evolved.

Other than that Ammonites, Corals, Amphibians and various other specialised invertibrates survived and carried on throughout the Triassic. Reptiles were for the most part the most dominating species of the Triassic but despite this the first mammals also appeared during this time period and were thought to have evolved from the mammal like reptiles (therapsids) that were common in the Permian period.

At this time the reptile scene was really starting to take over Dinosaurs (Land Reptiles), Pterosaurs(Flying Reptiles), Plesiosaurs (Marine Reptiles), Ichthyosaurus (Fish Reptiles) all started appearing. This was a great period for Archosaurs and the various other diapsid reptiles which were slowly taking over from the synapsids of the Permian period.

Other animals of note which also made a first appearance in the Triassic include turtles, frogs, crocodiles, and many types of lizards.

Despite the Triassic being the birth time of the dinosaurs they were still small and didn’t fully develop into the massive land reptiles we imagine them as until the Jurassic period. Some examples of the dinosaurs that made an appearance include:

* Coelophysis
* Eoraptor
* Plateosaurus

The Late Triassic Extinction :

When the Triassic Period was about to end another mass extinction not quite as damaging as the first occurred. The worst damage was made to marine life where most marine reptiles except the plesiosaurs and the ichthyosaurs died out.

On the land many of the large archosaur reptiles, labyrinthodont amphibians, Conodonts as well as some of the early dinosaur species all went extinct. This was a huge filteration process with many species completely eradicated from the planet. This however meant that the remaining dinosaurs were left as the largest land animals on the earth which set them up for complete domination into the Jurassic.

Just like most events this far back there is no clear answer as to what caused this extinction. Certainly the super continent although still in one piece had started to split and huge volcanic eruptions have been recorded during this time period. Other theories include a metoer as well as planetary cooling. We really don’t know but what we do know is that whether out of pure luck or sheer genius the dinosaurs were automatically given a clear path to success after this major extinction process.

Source from :http://www.dinosaur-facts.com

For more information related to dinosaurs, visit rareresource.com.

Jurassic Period

Introduction :

The Jurassic Period is the second phase of the Mesozoic era and quite possibly the most interesting. It spanned a total time period of around 65 million years and started around 205 million years ago right up to about 135 million years ago. It was named after the Jura mountains which are located between the border of Switzerland and France for the simple reason that the first rocks of the jurassic period were found and studied there.

A Splitting Super Continent :

Although the super continent had started to show signs of splitting in the latter part of the Triassic it didn’t actually split until the middle of the Jurassic period around 180 million years ago. The initial split left 2 continents a northern part called Laurasia (mainly North America and Europe) and a southern part called Gondwana (mainly South America, Africa, Australia).

Throughout the Jurassic and the rest of the Mesozoic era these continents continued to drift apart causing the formation of new oceans and the flooding of many parts of these once arid and super dry central regions. All this extra water meant that deserts and previously uninhabitable regions were slowly turning into swamps and tropical forests which would change the face of the Earth forever.

Jurassic Plant Life :

The above mentioned splitting and major break up of the super continent created not only a fresh new tropical environment for the next generation of dinosaurs but one that was greener and richer in plant life. The Jurassic weather was warm and the dampness provided by the early ocean exposure ensured that topical forests and plant life was plentiful.

Forests of ferns, seed ferns, ginkgoes, cycads and conifers were common and the first flowering plants also started to appear later in the Jurassic. This was indeed a fine time for plant life and one that would form the foundation for modern day angiosperms.

Jurassic Animal Life :

The Jurassic Period was called the “Age of the Ruling Reptiles”. Unlike the Triassic period, dinosaurs were now much larger which clearly put them at the top of the food chain. These extra large reptiles were the dominating species now and the Jurassic period marked their golden years.

Some of the largest dinosaurs of the Jurassic were the herbivore plant eating sauropods. Thanks to the abundant plant life massive herbivores such as the Brachiosaurus, Diplodocus and Apatosaurus had no shortage of food and enjoyed a level of comfort not previously enjoyed by the Triassic dinosaurs.

Just like the terrestrial herbivores of the Jurassic the carnivores were also a lot larger than their Triassic counterparts. The fiercest of these were extremely large theropods like the Allosaurus and the Ceratosaurus. The Allosaurus was probably the top Jurassic Predator of its time and with the largest specimen coming in at a length of over 9 metres its prey was most likely the large herbivores such as the sauropods. As a quick reminder thanks to movies like Jurassic Park its a common misunderstanding that the Tyrannosaurus Rex also existed during the Jurassic period when in actual fact it came into existance much later in the Cretaceous period. Other dinosaurs that fall under this misconception include the Triceratops who also existed much later in the Cretaceous.

Flying reptiles like the Pterosaurs were still the dominant air species but during the Jurassic we also find the appearance of the first primitive bird like species in the form of the Archaeopteryx. Despite having more in common with dinosaurs than modern day birds it was still the first feathered flying species and clearly an evoloutionary step towards the bird species.

Jurassic marine reptiles consisted mainly of the plesiosaurs, ichthyosaurs, large marine crocodiles, variations of modern day sharks as well as cephalopods which are relatives of todays squid and octupuss species.

More Extinctions:

Unlike the Triassic most of the land dinosaurs and reptile families that existed in the latter Jurassic period were also still in existance in the early Cretaceous. So unlike previous periods there were no mass extinction event that denoted the end of the Jurassic period.

Source from :http://www.dinosaur-facts.com

For more information related to dinosaurs, visit rareresource.com.

Cretaceous Period

Introduction:

The Cretaceous Period was the last phase of the Mesozoic era and spanned for an interval of 75 million years from 135-65 million years ago. Although the dinosaurs died out in this period many interesting dinosaurs like the Tyrannosaurus Rex and the Triceratops appeared making this period quite interesting.

Other important things that happened during the cretaceous included further splitting of the pangea breaking it down even further into the smaller continents we recognise today.

The cretaceous also denoted a start in the appearance of flowering plants like magnolias and water lilies as well as many of the modern insects we know of today. Examples include ants, butterflies, grasshoppers, termites and aphids. All of the above meant that the cretaceous truly was a an amazing and diverse period for life on the planet earth, sadly it was also the end of the dinosaurs but with over 180 million years of domination I don’t think they can complain.

More Pangea Splitting :

Ever since Laurasia split from Gondwana in the jurassic further splits and rifts within these 2 lesser continents continued to happen during the cretaceous.Gondwana finally split into four smaller pieces namely Africa, South America, India and Antarctica/Australia whilst Laurasia was still moving further away into the northern hemisphere.

This splitting of the Earths major land masses would continue well on into the Cenozoic era even after the dinosaurs had become extinct until it would finally resemble what we see on modern day maps. Remember these rifts are still happening today and maybe in millions of years from now the landscape of the earth will change once again.

High Ocean Levels :

During the cretaceous period the sea levels rose all over the world resulting in the submerging of at least one third of the earth’s land area. Why there was so much water can be attributed to three possible reasons.

* There were no frozen poles during the cretaceous (or jurassic), this reason alone meant that water levels were generally higher during the Mesozoic era.
* In general because of the higher temperatures that existed during this time a thermal expansion of the ocean waters meant a greater volume for the same mass of water. If we look at the temperatures on the ocean bed today they are close to 3-4 degrees centigrade whereas during the cretaceous they would have been as high as 15 degrees centigrade which demonstrates a real difference in overal temperatures.
* Both the jurassic and the cretaceous contained huge levels of volcanic activity thanks to the constant tectonic changes happening within the earth. This meant that much of the oceans surface consisted of erupting volcanoes filling the sea bed with mini mountain ranges thus making the oceans extremely shallow and causing them to contain less water thus flooding much of the earths then low lying land.

General Climate :

As far as living species were concerned temperatures were much lower and more importantly stable for most of the cretaceous. Compared to the triassic and jurassic periods better temperatures meant created a much more hospitable environment for animals and plants to diversify.

This massive climate change was mainly due to the changes happening at the tectonic level, the cretaceous was in general a much wetter period with oceans flooding the land to create many lakes, rivers and swamps.

All this extra water offered great opportunities for diversification in both animals and plants, of course the tectonic movements much volcanic activity which as we shall see had a massive impact on temperatures towards the end of the cretaceous period where global warming and a possible asteroid hitting the earth caused the massive dinosaur extinction commonly referred to as the cretaceous tertiary extinction

Cretaceous Plant Life :

The biggest change in the cretaceous had to be the appearance and advancement of flowering plants. Until now the dominant plant life consisted of cycads, seed ferns and confiers. The introduction of flowering plants added a totally new dimension to the ecological landscape and by the end of the cretaceous they pretty much took over as the dominiating plant species.

The plant life during the cretaceous took a very modern appearance making the landscape very similar to todays tropical jungles and forests. The angiosperms success and spread during the cretaceous was significant in supporting the birth of many new insect and mammal species. This was truly an exceptional and hugely diverse time for both animals and plants, and one that would start the end of the dinosaurs and the start of new life in the cenozoic era.

Cretaceous Animals :

In the Cretaceous period dinosaurs reached the peak of their dominance. It was during this time that the horned dinosaurs like the Centrosaurus and Triceratops appeared. The duckbilled Parasaurolophus, the armored Ankylosaurus, and the well known Tyrannosaurus also made their first appearance during the cretaceous.

Both birds and the flying reptiles such as the pterosaurs were now much more developed and completely dominated the skies.

In the sea ichthyosaurs, plesiosaurs and sharks continued to dominate marine life as they did in much of the jurassic. However new predators namely Mosasaurs who were snake like reptiles also came into existance during this hugely diverse time period. These ferocious creatures lived in lagoon and shallow water areas where they would aggressively ambush passing prey. Other animals that appeared in the cretaceous include large crocodiles, turtles, snakes and lizards.

Dinosaur Extinction :


At the end of the cretaceous period a mass extinction second only to the permian triassic extinction wiped out over 80% of all living species on the planet earth. It wasn’t just the dinosaurs that were affected, pterosaurs, mosasaurs, plesiosaurs, ammonites, belemnites and many other species which were common at that time simply dissappeared.

Its not 100% clear what caused the extinction but some key factors which certainly contributed to it include the striking of a massive asteroid approximately 10 kilometres in diameter. This asteroid landed in the Yucatan peninsula in Mexico and would have had disasterous consequences ranging from forest fires to sunlight blocking dust and causing mass darkness and death to both animal and plant life.

Of course there are other theories related to huge volcanic eruptions, global warming and even disease amongst the dinosaurs. Again nothing is confirmed except that the death of the dinosaurs paved the way for a new wave of mammal species which took over and dominated in the Cenozoic era.

Source from :http://www.dinosaur-facts.com

For more information related to dinosaurs, visit rareresource.com.

Ankylosaurus dinosaurs

Origins & Name :

The Ankylosaurus was a heavily plated, four legged herbivore which originally emerged in the Jurassic period but spread rapidly during the Cretaceous, by which time it was flourishing in the northern continents and even as far south as Australia and Antarctica.

Discovered by Barnum Brown in 1908, it was popularly referred to as the “fused” or “curved” lizard owing to its Greek roots ‘ankulos’. The remains of the ankylosaurus were discovered in different parts of North America, more specifically in the Lance Formation in Wyoming, Hell Creek aswell as the Scollard Formation in Alberta, Canada.

Taxonomy :

Belonging to the Ankylosaurid genus the Ankylosaurus only had one species the A. magniventrisare. The term ‘magniventris’ has a specific meaning and here it can be traced back to its Latin origins where ‘magnus’ refers to great or large while ‘ventris’ refers to the belly. Therefore the A. magniventris refers to the enormous extent of the ankylosaurus.

All descendents of the ankylosaurid group are recognisable for their bony tail club and hugely armored body. In fact the ankylosaurus are considered to be symbolic of the standard armored dinosaur.

Physical Features :

The ankylosaurus was the largest of the ankylosaurids and measured anything from 20-30 ft long. With an extremely wide and bulky frame the ankylosaurus was the tank of dinosaurs in more ways than one.

The Tail Club :

One of the most prominent features of the bone structure of the ankylosaurus was its tail club. The vertebrae of the tail region was formed as a series of huge osteoderms which are actually bone plates. These bone plates were interconnected with seven tail vertebrae joining together providing enormous strength to the base of the club. If enough strength and power wasn’t enought they also possessed several bony tendons which infused extra power to the tail allowing it to be used effectively as a defensive weapon. It’s thought that a single strike of the tail could break the bones of it’s attacker.

Body Plates (Armor):

While the tail club formed a significant part of the body of the Ankylosaurus, a further unique feature of it’s physical appearance were the body plates or the layers of osteoderms that covered its entire body. These plates formed an armor which added to the defensive strategy of the Ankylosaurus.

Head & Skull :

The head and skull of the Ankylosaurus was more or less triangular in shape and much wider compared to its length. This structure is common for herbivores who mostly fed from the low lying vegetation on the ground and not from the high branches of trees like those of the Corythosaurus.

Like most herbivores the ankylosaurus possessed small leaf shaped teeth which were suitable for chewing. No specialized grinding teeth were found which provides evidence that there food type was limited to foods that were easily chewable.


Source from :http://www.dinosaur-facts.com

For more information related to dinosaurs, visit rareresource.com.

Coelophysis

Coelophysis Origins :

The Coelophysis was a small carnivorous dinosaur whose existance dates back to the Triassic period over 228 million years ago. It owes its name to the Greek root word “Koilos” which refers to something hollow while “Physis” simply refers to a form or structure. Their name emphasises their light and hollow bone structure.

The very first specimens of the Coelophysis were first discovered in 1881 by David Baldwin and was quickly named C. Baur. However these fossil samples were not enough to give scholars any real data on this new dinosaur species.

While researchers continued to work, it was in 1947 that a huge grave of Coelophysis fossils were unearthed in the Ghost Ranch in New Mexico. Not only was this a great find but it was the first time such a huge collection of dinosaur fossils had been excavated in one go. Finds like this usually presume that these dinosaurs were swept away as a result of some natural hazard like a flash flood and buried instantly.

Taxonomy :

The Coelophysis was initially considered to belong to a single species, that of the C. Bauri. However, there are two other kinds which have been recently added as a variant of this type, namely the C. willistoni and C. longicollis which are known to have no other similarities except that they all belong to a similar genetic structure.

Physical Features :

The Coelophysis was a slim theropod which was probably as long as a car but as light as a 7 year old. They were one of the earliest dinosaur species and despite only being 2-3 meters in length were vicious pack hunters.

There light weight and hollow bone structure was a big deal and despite being a theropod, their early existance meant they carried several features which were considered to be the first of a kind in dinosaurs. Other features such as having 4 digits on each hand as opposed to 3 offers a great example of features which were later lost by theropods.

These early dinosaurs had a long head, an elongated snout and a noticably long curvy neck. Add to this extremely slender limbs and this reptile almost resmbled a bird. However unlike birds the Coelophysis had teeth, clawed hands and a long bony tail.

Swift Commuters :

The most interesting section of the body was probably their vertebra which were arranged in such a way that they prevented the long tail from constantly moving up and down. This combined with their super light weight may have contributed to their ability to commute swiftly.

Behavioral & Hunting Patterns :

Most of the information regarding the life and times of the Coelophysis was obtained from the fossil specimens that have been discovered from the Ghost Ranch in New Mexico. As stated before the Coelophysis were meat eaters and probably hunted other small lizards and small mammals.

Not dissimilar to scavengers, they probably hunted in packs and pounced on their prey digging their edged and jagged teeth into their prey. Their teeth were extremely sharp on both edges and therefore easily pierced unarmored skin. Like most hunters the Coelophysis probably lost and regrew its teeth throughout its lifetime.
Cannibalistic Or Not ?

Severeal researchers have also pointed that in their initial stages the Coelophysis may have displayed cannibalistic traits. This claim was originally supported by various studies of the abdominal cavity of certain fossil specimens which revealed the presence of other Coelophysis samples. Whether this is 100% accurate or not is debatable as other scientists believe those specimens were in actual fact Crutotarsan reptiles.

Source from :http://www.dinosaur-facts.com

For more information related to dinosaurs, visit rareresource.com.

Corythosaurus dinosaurs

Corythosaurus Origin :

The Corythosaurus was a crested duck-billed dinosaur which existed during the late cretaceous period around 80 million years ago. The name Corythosaurus means “Helmet Lizard” which stems from the Greek words ‘korythos’ meaning helmet and ’saurus’ meaning lizard. The name was given due to the similarity between the crest on it’s head and the helmets worn by soldiers in ancient Greece.

Bernard Brown discovered the very first Corythosaur skeleton in the Red Deer River valley in Alberta, Canada in 1912. But unlike other discoveries this one was a little different because instead of just uncovering a few remnants this was a complete head to toe fossil so well preserved that it even carried fossilised skin. It’s no coincidence that this well preserved fossil led to the Corythosaur becoming one of the worlds better known dinosaurs (it was even featured in Jurassic Park).

Taxonomy :

The hadrosaurids or the duck-billed dinosaurs have been classified by scientists and paleontologists into two prominent groups, namely the hadrosaurinae and the lambeosaurinae. The Corythosaurus belonged to the second group due to its crested skull.

In terms of species there were about seven different variants of the Corythosaurus acknowledged by scientists. These included the C. excavatus, C. casaurius, C. intermedius, C. frontalis, C. brevicristatus and C. bicristatus. However in later years it’s thought that this classification was incorrect and therefore currently only the C. casaurius is recognized as the sole Corythosaurus species.

Physical Features :

The Corythosaurus were over 30 ft tall and weighed about 4 tonnes. These were big dinosaurs and for this reason were also considered great prey for the likes of the Tyrannosaurus Rex, who was known to hunt them regularly.

Skull & Teeth :

The frontal portion of their skull was usually flattened and protruded outwards to form a beak. As herbivores this was extremely helpful when they collected leaves and twigs from the branches of high trees.

Interestingly enough no teeth were present in the front of the beak but despite this the Corythosaurus had an extremely well defined dental arrangement at the rear. A selection of almost perfect molars and incisors were present for the cutting, chewing and grinding of tough vegetation such as magnolia leaves, twigs, foliage, cycads, pine and conifer leaves.

The skull of the Corythosaur was unique in another way, it accommodated nasal channels which granted the species a great sense of smell and the ability to create loud sounds. The use of high pitched sounds may have been helpful in alerting others of danger, food or simply to communicate over long distances.

Webbed Feet :

The limbs of the Corythosaur consisted of three digits and were padded, similar to the webbed feet of ducks. Initially this characteristic threw scientists off, leading them to believe the Corythosaurus was an aquatic species. It was only later that these theories were abandoned after realising the webbing was simply deflated padding.

Behavioral Patterns & Hunting :

Not much information is available on the behavioral patterns of these dinosaurs but it’s generally believed that they were extremely timid and most likely herding animals who formed nesting colonies.


Source from :http://www.dinosaur-facts.com

For more information related to dinosaurs, visit rareresource.com.

Giganotosaurus

Giganotosaurus Origins

The Giganotosaurus existed during the Turonian stage of the late cretaceous period about 90 million years ago. It was first discovered in 1995 in the Argentinean region of Patagonia at the Rio Limay Formation by Ruben Carolini. The meaning of the name stems from the Greek word ‘gigas’ meaning giant, ‘notos’ referring to the south and the term ‘saurus’ meaning lizard, giving us the ‘giant southern lizard’

As its name suggests the Giganotosaurus is considered by scientists to be the largest of the terrestrial carnivorous dinosaurs, even larger than the ferocious predator Tyrannosaurus Rex.



Taxonomy

The Giganotosaurus was a member of the Carcharodauntosaurid dinosaurs who were a group of ultra large theropod dinosaurs. The Carcharodauntosaurid family contained some of the largest carnivorous predators of all time, apart from the Giganotosaurus other members included the Mapusaurus, Carcharodontosaurus, and the Tyrannotitan. The family to surpass the Carcharodauntosaurids in size were the Spinosaurids.



Physical Features

The Giganotosaurus was a mammoth sized carnivore which measured around 45 ft in length and weighed a little over 6 tonnes, surpassing the T. Rex by a small margin. Like most Theropods the Giganotosaurus had a prominently visible and large head and is believed to have possessed the longest skull among the various theropod dinosaurs.

With such a large skull there was space for a very well developed olfactory region suggesting an extremely sharp sense of smell. However it’s worth mentioning at this point that skull size isn’t everything, as despite the Giganotosaurus having a larger skull its brain was almost half the size of the Tyrannosaurus.

Now compared to the T. Rex whose teeth were ideal at snapping and cutting through bone, the Giganotosaurus had much smaller, narrower and more evenly sized teeth. This would have made them ideal for slicing flesh and leaving deep cuts in their victims as opposed to the bone crushing effect that the T. Rex had.



Behavioral Patterns & Hunting

Thanks to its size, scientists believe the Giganotorsaurs was more than capable of going after the super sized herbivores such as the Argentinosaurus and the Titanosaurus. In fact Titanosaur fossils were found extremely close to those of the Giganotosaurus making this an even higher possibility.

In terms of hunting style unlike the Tyrannosaurus who was a solitary hunter scientists believe the Giganotosaurus may well have been a pack hunter. The reason for this stems from the study of the other Carcharodauntosaurid dinosaurs whose fossils were often discovered in groups, indicating a collective hunting or herd like grouping. With the Giganotosaurus this is even more likely as going after the super sized herbivore giants would have been no easy task on ones own, but as a pack it may well have worked quite well.

Source from :http://www.dinosaur-facts.com

For more information related to dinosaurs, visit rareresource.com.

Tyrannosaurus Rex

Tyrannosaurus Origins

The Tyrannosaurus or T. Rex existed in the late cretaceous period some 65 million years ago. A carnivorous dinosaur and an extremely popular icon in todays movie culture this dinosaur is probably one of the most talked and read about dinosaurs ever to have existed. With some amazing scenes in both Jurassic Park and the recent King Kong movie it’s no wonder he’s so popular.

The name Tyrannosaurus Rex means ‘Tyrant Lizard King’ which stems from the Greek word ‘tyranno’ meaning tyrant, ’saurus’ meaning lizard and ‘rex’ meaning king. The grand name comes directly from the fact that the T. Rex was most probably one of the largest and most terrifying carnivores of its time.



Taxonomy

The Tyrannosaurus a bipedal theropod was a part of the Tyrannosaurid family which existed in most parts of western north America as well as some parts of Asia. For a long time it was believed that the T. Rex was the largest carnivorous dinosaur of them all, but that was before the Giganotosaurus and Carcharodontosaurus were discovered.

Despite not being the largest of the carnivores it was still the largest member of the Tyrannosaurid family and of course recognised as one of the fiercest land predators ever to exist. Over time scientists have classified and re-classified discoveries in and out of this group as quite clearly the tyrannosaurid group is a bench mark in its own right.

As an example in 1955 Russian paleontologist Evgeny Maleev named a new species called Tyrannosaurus bataar which was discovered in Mongolia. By 1965 this species had been regrouped adn renamed to Tarbosaurus bataar. Despite the renaming it’s still thought of being a close sister and asian version of the Tyrannosaurus rex.



Physical Appearance

At over 20 ft tall, 40 ft long and weighing up to 8 tonnes the Tyrannosaurus was longer than the width of a tennis court, heavier than an african bull elephant and tall enough to look into an upstairs window. It’s massive legs bore its weight on three large, bird like clawed toes, whilst its arms which despite being extremely short were strong and powerful with 2 clawed digits.



Large Skull

One feature that stood out in all Tyrannosaurids was the size of their skull. In simple words it was huge and at 5ft long the skull was almost half as long as the backbone between the hips and the head. The head was basically the size of a small car and considered huge even for dinosaurs.

To support such a large head the T. Rex had an extremely short but muscular neck giving it extra strength and allowing it to stabilise the head as it moved. Obviously a huge skull meant plenty of room for large teeth which were so hard that they were known to penetrate even bone.

All these characteristics meant that the Tyrannosaurus Rex had one the strongest bite forces of any dinosaur that ever existed. The pressure exerted in a single bite was equivalent to around 4 tonnes per square inch. Obviously with such a mean bite teeth are bound to be lost which luckily for the T. Rex and the rest of the tyrannosaurid family grew back throughout its life.



Vision & Smell

The T. Rex had a small brain in proportion to its body, but even so it was larger than most other dinosaurs. Its eyes were positioned on the front of the skull which is very similar to the way human eyes are positioned, and would have meant its ability to focus and judge distance objects was very good.

Scientists also believe that a large portion of the brain was allocated to smelling making the T. Rex a very strong sniffer. If you combine the strength of the eyes with the strong sense of smell you very quickly appreciate how these two natural abilities would have made the Tyrannosaurus a very effective predator.



The Tail

As well as a large head the Tyrannosaurus also possessed an equally large and stiff tail. Most scientists believed the weight of the tail would have meant it dragged on the floor as it moved, however more recent studies challenged this stating that the tails weight formed a counter balance to the extremely heavy head. If this were the case then it would actually be carried in the air to counter the heavy head which would have been in a forward leaning position.



Tiny Arms

Despite having arms that were only 2-3 ft long they were still however extremely muscular and able to support hundreds of pounds of weight.

So what were these arms used for ? Well a number of theories are plausible and one of them is that the arms were used to assist the T. Rex whilst lifting itself off the floor. Others say that the two sharp claws on each arm were used to hold its prey whilst it devoured them with its mouth.



A Quick Size Comparison

When we start to talk about the Tyrannosaurus and its huge head it’s very easy to forget what it’s overall size was in comparison to the long necked sauropod herbivores. Some examples include the Sauroposeidon which is the tallest known dinosaur and stood at 55 ft (17 metres) in height, the T-Rex as you can see was almost a third of its height.

In fact there were even larger sauropods such as the Argentinasaurus who was 115 ft long (35 metres) and weighing between 80-100 tonnes. Compare that to the T. Rex which was only 6-8 tonnes and 40 ft in length and you quickly realise the size difference. We throw this section in because most readers get so amazed with the grandness and power of the T. Rex that they often forget his overall size in comparison with the rest of the dinosaurs.



T-Rex Top Speed

The Tyrannosaurus Rex had one of the strongest not to mention longest legs of any Theropod. These massive legs combined with three huge toes on each foot meant the T. Rex was able to take very long strides covering distances of up to 15 ft with each step, thus giving it a top speed of around 25 mph.



Behavioral Patterns & Hunting

It’s thought that the T. Rex probably lived close to its prey which were in most cases plant eating herbivores. This would imply that its primary dwelling would have been near forests, open woodland, rivers and valleys rich in plant life.

We know the T. Rex was probably well suited to hunting but how it hunted is an issue up for debate. Most scientists feel that due to the lack of fossil evidence suggesting group hunting, it was most likely a solitary hunter.

How it fared against other dinosaurs who did hunt and exist in packs is an interesting question. Some have said the T. Rex possessed such a powerful bite that this alone would have been a huge deterrant and factor in maintaining its superiority over other large dinosaurs and pack hunters.

It’s absolutely certain that the Tyrannosaurus would have eaten large dinosaurs if they were already dead but may also have attacked animals that were either too young, sick or old to protect themselves. Some scientists believe this behaviour is scavenger like whilst others feel it’s just a fact of life.



T. Rex Prey

In terms of what and who it preyed upon, there’s fossil evidence to suggest it commonly consumed both Triceratops and the duck-billed Hadrosaurs such as the Corythosaurus. In most cases scientists feel that an initial power bite would have severely crippled its prey causing massive blood loss. This would eventually cause its prey to lose strength and even collapse. At this point the T. Rex could quickly use both its foot claws and mouth to finish off its opponent.



Fossils

In total around 30 Tyrannosaurus Rex fossils have been recovered with the first T. Rex fossil being discovered in 1902 by Barnum Brown in South Eastern Montana, USA. Most other T-Rex fossils were also found in this region but some have also been found in Canada and parts of Asia such as Mongolia.

Source from :http://www.dinosaur-facts.com

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